From b8b9ccf201219fe01d502c9d78e748e937e5e8a3 Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Sun, 6 Dec 2020 21:10:20 +0100
Subject: [PATCH] Reset scale when update spread mode

---
 web/base_viewer.js            | 23 ++++++++++++++++++-----
 web/pdf_single_page_viewer.js |  4 ++++
 2 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/web/base_viewer.js b/web/base_viewer.js
index 060cf331f79bdc..519f35b112aa4a 100644
--- a/web/base_viewer.js
+++ b/web/base_viewer.js
@@ -725,6 +725,20 @@ class BaseViewer {
     }
   }
 
+  /**
+   * @private
+   */
+  get _pageWidthScaleFactor() {
+    if (
+      this.spreadMode !== SpreadMode.NONE &&
+      this.scrollMode !== ScrollMode.HORIZONTAL &&
+      !this.isInPresentationMode
+    ) {
+      return 2;
+    }
+    return 1;
+  }
+
   _setScale(value, noScroll = false) {
     let scale = parseFloat(value);
 
@@ -735,10 +749,6 @@ class BaseViewer {
       if (!currentPage) {
         return;
       }
-      const factor =
-        this.spreadMode === SpreadMode.NONE || this._isScrollModeHorizontal
-          ? 1
-          : 2;
 
       const noPadding = this.isInPresentationMode || this.removePageBorders;
       let hPadding = noPadding ? 0 : SCROLLBAR_PADDING;
@@ -750,7 +760,7 @@ class BaseViewer {
       const pageWidthScale =
         (((this.container.clientWidth - hPadding) / currentPage.width) *
           currentPage.scale) /
-        factor;
+        this._pageWidthScaleFactor;
       const pageHeightScale =
         ((this.container.clientHeight - vPadding) / currentPage.height) *
         currentPage.scale;
@@ -1481,6 +1491,9 @@ class BaseViewer {
     }
     this._setCurrentPageNumber(pageNumber, /* resetCurrentPageView = */ true);
     this.update();
+    if (this._currentScaleValue && isNaN(this._currentScaleValue)) {
+      this._setScale(this._currentScaleValue, true);
+    }
   }
 }
 
diff --git a/web/pdf_single_page_viewer.js b/web/pdf_single_page_viewer.js
index 1e835897d08962..20b340e1336d09 100644
--- a/web/pdf_single_page_viewer.js
+++ b/web/pdf_single_page_viewer.js
@@ -35,6 +35,10 @@ class PDFSinglePageViewer extends BaseViewer {
     return shadow(this, "_viewerElement", this._shadowViewer);
   }
 
+  get _pageWidthScaleFactor() {
+    return 1;
+  }
+
   _resetView() {
     super._resetView();
     this._previousPageNumber = 1;